docs: def extract_event_info(dstore, eidx):
      """
      Extract information about the given event index.
      Example:
      http://127.0.0.1:8800/v1/calc/30/extract/event_info/0
      """
      event = dstore['events'][int(eidx)]
      serial = int(event['eid'] // TWO32)
      ridx = list(dstore['ruptures']['serial']).index(serial)
      [getter] = getters.gen_rupture_getters(dstore, slice(ridx, ridx + 1))
      rupdict = getter.get_rupdict()
      rlzi = event['rlz']
      rlzs_assoc = dstore['csm_info'].get_rlzs_assoc()
      gsim = rlzs_assoc.gsim_by_trt[rlzi][rupdict['trt']]
      for key, val in rupdict.items():
          yield key, val
      yield 'rlzi', rlzi
      yield 'gsim', repr(gsim)